Means for drawing parallel lines



Dec. 12, 1939.

H. L. DE LISLE MEANS FOR DRWING PARALLEL LINES Filed Jan. 2l, 1938 ff ff a, if ab j@ j fic j! 25 2 ab i! j jj 30.

Patented Dec. 12, 1939 UNITED STATES rATENT OFFICEV 2 Claims.

This invention relates to means for drawing parallel lines at a given distance apart and is of particular utility to rolraftsmen or the like.

Among other objects the invention aims to provide improved and simplified means of this character which requires a minimum of adaptation to existing drafting devices.

Other objects and advantages will be apparent from the following description taken together with the accompanying drawing, in which:

Figure l is a plan view of my improved means, on say full scale;

Figure 2 is an enlarged cross-section taken on the line 2-2 of Fig. 1;

Figure 3 is a bottom view of the device shown in Fig. 2; and

Figure 4 is a partial cross-section taken on the line ll-2 of Fig. 1.

Referring in detail to the illustrative construction shown in the drawing, the triangle I0 may be the usual draftsmans triangle constructed of transparent material as is well known in the art. The edges II and l2 may be right-angularly related one to the other, and the edge I3 a hypotenuse thereof. These edges II, I2 and I3 may be champfered on their under side as at Ill, as best shown in Fig. 4, and as partially indicated in Fig. l, in order tov minimize danger of blurring when a pen is used` with the triangle.

In addition to the usual central cut-out portion l5 of the trianglain accordance with the present invention the triangle Il) as here shown has at least one and in this instance three relatively narrow elongated slots I6, Il and I8, one of these slots being parallel with ,each `of the edges I I, l2 and I3, respectively, of the triangle.

For cooperation with these slots, means, next described, are provided for moving the triangle a predetermined distance rectilinearly for the purpose of drawing a series of parallel lines I9, for example, a given distance, in this instance three-sixteenths of an inch, apart.

Further in accordance with the present invention, and as best shown in Fig. 2, a member 20 is provided for the purpose just mentioned, preferably oi beetle shape, and desirablymade of saycast bronze or any other suitable material having considerable weight for its size. The bottom of the member 2li is channelled as at 2 I this channel being of approximately the length and width of the slots in 'the triangle. Reciprocally secured in the channel 2i are a pair of longitudinally aligned cylindrical feet 22, each having an extension 23 through an elongated aperture 2li of which passes a clamping screw 25. The portions 24 fit snugly but slidingly in the channel 2l and the feet may be reciprocated in the channel limited by the relative movement of the screw 25 and elongated aperture 24. The head ofthe screw prevents displacement of the feet from the channel.

For purposes of reciprocating the feet 22, each of the extensions 2li of the feet, has, in this instance, a perpendicular bearing portion 25 which projects into the enlarged central recess 21 in the member 2U, this recess communicating with the channel 2l. The bearing portions 26 are therefore parallel and oppositely related. The rod 28 having oppositely threaded ends 28a and 28h and a central thumb-wheel 29 is supported by the bearing portions 25, each of the ends having threaded engagement with `a tapped perforation in the bearing portions 26. The thumbwheel 29 projects revolubly through an opening 30 in the member 2Q opening into the top surface of this member and communicating with the recess 21, the extent of projection of the thumb- Wheel into the opening being just suicient to permit the thumb of the operator to frictionally contact the thumb-wheel, preventing axial movement of the rod 28.

By the construction just described, it will be understood that a certain degree of rotation of the thumb-wheel 29 will cause reciprocation of the ieet 22 toward or away from each other to extend or contract the distance between these feet. By suitable arrangement of the pitch of the threads 28a, 28h, a given partial rotation of the thumb-wheel 29 will move the feet 22 toward or away from each other a distance of say onesixteenth of an inch, one complete revolution of the thumb-wheel movingthe feet the full distance permitted which will `be say five-sixteenths of an inch. To enable the operator to determine the distance which the feet will move, the periphery of the thumb-wheel may be graduated by siXteenths of an inch as indicated at 3l.

Thus, for example, when the feet are at the farthest distance apart, the thumb-wheel 29 may have its Zero graduation registered with a xed mark 32 on the bodyy of the member 20 adjacent the opening 3S. At that time the member 20 may be superposed on the triangle lil and carried therewithin with the feet 22 received in say the slot I6 of the triangle and with the feet contacting the ends of this slot. At this time, by means of the upper edge I2 of the triangle, the uppermost of the parallel lines I9 would have been drawn. If now it be desired to draw the remainder of the parallel lines I9 and at a distance of three-sixteenths of an inch apart, the

operator may rotate the thumb-wheel 29 until the graduation on the periphery of the wheel indieating three-sixteenths of an inch is in register with the mark 32. When this has been done, the feet 22 will be drawn together a total distance of three-sixteenths of an inch.

It will be understood that the feet 22 are of suiicient depth to contact the drawing 33, through the slot I6, the amount which the feet project below the body 20 being slightly greater than the thickness of the material of the triangle I0, as best shown in Fig. 2. To minimize slippage of the feet on the drawing 33 when desired to maintain them stationary, the feet 22 are undercut as at 34 to provide somewhat sharp edges 35 thereon.

Having adjusted the device 20 for successive movements of three-sixteenths of an inch, the operator next moves the device 20 downward, as shown in Fig. 1, to the limit of its movment in the slot I6, as would be determined by abutment of the lowermost foot 22 with the lowermost end of the slot IB. This may be done with the left hand of the operator while maintaining the triangle stationary with the right hand. Thereupon, while maintaining with the left hand the device 20 stationary with respect to the drawing 33, the operator moves the triangle I0, with the right hand, downward a distance limited by the play of the feet 22 in the slot IB which in this instance has been predetermined to be three-sixteenths of an inch. At this time the uppermost foot 22 is in contact with the uppermost end of the slot I6 as shown in Fig. 1. By holding the device 20 stationary with the left hand the triangle I0 is also held stationary from any downward movement, and its edge I2 is parallel with, but three-sixteenths of an inch downward from the uppermost parallel line I9, whereupon the operator draws another of these parallel lines. Then the operator again moves the member 20 downwardly in the slot I6 to the limit of its movement while maintaining the triangle stationary, and then holds the member 20 stationary while moving the triangle downward to the limit of its movement, whereupon another parallel line I9 may be drawn similarly spaced from the next uppermost line. This may be repeated until the number of parallel lines desired has been drawn.

It will be understood that the member 20 may be used with any one of the slots I6, I'I or I8 and for a similar purpose to that just described.

In order to place a tension upon the thumbwheel 29 and prevent accidental displacement thereof, the compression coil spring 36 may be disposed between the thumb-wheel and one of the bearing portions 26.

In order to reduce the contacting surface area of the triangle, the triangle is desirably recessed on its faces, in addition to the cut-outs already referred to, by grooves |00 along the margins of the triangle. As so reduced, the area of the triangle which contacts with the drawing or tracing is so diminished as to minimize blurring of the drawing by the triangle or friction therebetween which has heretofore been inherent in the devices of the prior art. To prevent the grooves |00 from forming suction cups, they desirably are vented as at IIJI, in this instance, to the cut-out portions I6, I1, or I8 as the case may be. It will be understood that the grooves |00 may be along each margin of the triangle and on both faces.

Having described my invention, I claim:

1. In a device of the class described, the combination with a draftsmans triangle or the like, having a relatively narrow elongated slot therein, of a member separable therefrom of greater area than said slot superposed thereabove within the area of the triangle and having a pair of feet receivable in said slot and projecting below the lower face of the triangle and means carried by the member for extending or contracting the distance between the said feet within the limits of said slot, said member being of somewhat heavy beetle-like formation extending well above said triangle to be readily grasped by the draftsman.

2. In a device of the class described for use with a draftsmans triangle or the like, the combination of a relatively heavy body having a central recessed portion and a pair of longitudinally extending aligned oppositely directed channels in its lower flat face opening into said recessed portion, a pair of feet for said body each foot having a ilat extension snugly slidable in one of said channels and having an elongated aperture therein, a clamping screw passing through each aperture into said body, the said foot extensions having perpendicularly directed bearing portions disposed in parallel within said central recess, tapped perforations in said bearing portion, a threaded rod passing through both said perforations and having a thumb-wheel iixed thereon, an opening from said recess through the upper surface of said body receiving the periphery of said thumb-wheel therethrough and a compression coil spring disposed on said rod between said thumb-wheel and one of said bearing portions to apply friction between said rod and said bearing portion whereby the thumb-wheel may be turned from the upper surface of said body to extend or contract the distance between said feet.

HAROLD L. DE LISLE. 

